This study examines the role of a particular kind of linguistic input--talk about the past and future, pretend, and explanations, that is, talk that is decontextualized--in the development of vocabulary, syntax, and narrative skill in typically developing (TD) children and children with pre- or perinatal brain injury (BI). Decontextualized talk has been shown to be particularly effective in predicting children's language skills, but it is not clear why. We first explored the nature of parent decontextualized talk and found it to be linguistically richer than contextualized talk in parents of both TD and BI children. We then found, again for both groups, that parent decontextualized talk at child age 30 months was a significant predictor of child vocabulary, syntax, and narrative performance at kindergarten, above and beyond the child's own early language skills, parent contextualized talk and demographic factors. Decontextualized talk played a larger role in predicting kindergarten syntax and narrative outcomes for children with lower syntax and narrative skill at age 30 months, and also a larger role in predicting kindergarten narrative outcomes for children with BI than for TD children. The difference between the 2 groups stemmed primarily from the fact that children with BI had lower narrative (but not vocabulary or syntax) scores than TD children. When the 2 groups were matched in terms of narrative skill at kindergarten, the impact that decontextualized talk had on narrative skill did not differ for children with BI and for TD children. Decontextualized talk is thus a strong predictor of later language skill for all children, but may be particularly potent for children at the lower-end of the distribution for language skill. The findings also suggest that variability in the language development of children with BI is influenced not only by the biological characteristics of their lesions, but also by the language input they receive.